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Biomedical subjects

A Domínguez

Publications and source records attributed to A Domínguez.

At least 19 recordsLinked to original sources

Cloning and sequencing of the URA5 gene from the yeast Yarrowia lipolytica.

The URA5 gene of Yarrowia lipolytica encoding the orotate phosphoribosyl transferase (OPRTase, EC2.4.2.10) was isolated by target integration in a mutant strain originally named ura2.21. The nucleotide sequence of the gene predicts a protein with high similarities with the OPRTases from Saccharomyces cerevisiae, Podospora anserina and Escherichia coli and to a lesser extent with that of Dictyostelium discoideum. The transcription start point has been mapped by primer extension analysis and indicates the existence of a long leader sequence in the corresponding mRNA. Northern-blot hybridization revealed the URA5 transcript to be approximately 0.94 kb. Deletion of the URA5 gene in Y. lipolytica produced a leaky phenotype similar to the one described for the ura5 mutation in S. cerevisiae. The URA5 gene of Y. lipolytica was able to complement functionally the ura5 mutation of S. cerevisiae.

Amino Acid Sequence

Selective inhibition of cytosine-DNA methylases by polyamines.

We have advanced the hypothesis that polyamines affect DNA methylation and thus promote the expression of developmentally controlled genes. We demonstrate that the activity of cytosine-DNA methyltransferases HpaII, HhaI, HaeIII and SssI is inhibited by physiological concentrations of polyamines. On the other hand, activity of the adenine-DNA methyltransferase EcoRI, and restriction enzymes HpaII, HhaI, HaeIII and EcoRI, is insensitive to polyamine concentrations up to 40 mM. Our results indicate that the effect of polyamines on cytosine-DNA methyltransferases is rather selective and suggest a possible mode of action in vivo.

DNA

Green hair.

Green hair is an unusual dermatologic condition usually due to the deposition of copper from exogenous sources. We report the cases of two patients who presented to our clinic with green discoloration of their hair. This pigmentation of hair has generally been reported in patients with blond hair as a consequence of increased concentrations of copper in domestic or swimming pool water. Although an increased copper content of the affected hair seems to be a prerequisite, other predisposing factors have to be present for this situation to occur. These include previous hair damage (mechanical, sun exposure, bleaching, dyeing, waving), frequent contact with chlorinated water, or use of alkaline shampoos. Several options for treatment have been described for this problem, including application of hot vegetable oil, hydrogen peroxide, edetic acid- or D-penicillamine-containing shampoos, or hydroxyethyl diphosphonic acid.

Adult

[Hepatitis E].

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Adolescent

[Seroepidemiology of hepatitis C virus infection in pregnant women in Catalonia].

BACKGROUND: The aim of this study was to investigate the prevalence of hepatitis C virus (HCV) infection in a population of pregnant women in Catalonia and the sociodemographic variables and risk factors associated to this prevalence. METHODS: A representative sample of the pregnant women in Catalonia (n = 4,551) randomly selected by clusters (hospitals with maternity clinics) was studied. Detection of antiHCV antibodies was performed by the third generation ELISA test. Reactive cases were confirmed with RIBA 3 and MATRIX. RESULTS: The prevalence of antiHCV was found to be 1% and was not significantly associated with any of the sociodemographic variables studied (age, social and cultural level, origin and residence). A history of blood transfusion, intravenous drug consumption and hepatitis in the sexual partner were the only risk factors associated with the prevalence of infection found on univariate analysis although these were only present in 47% of the antiHCV positive cases detected. The association between the positivity of antiHCV and the history of hepatitis in the partner was lost on stratification of the cases according to the possible existence of history of drug addiction. CONCLUSIONS: A high proportion of young asymptomatic people (1%) were found to have hepatitis C virus infection with the possible mode of infection not being detected in approximately half of these subjects. In the other half of these cases the infection was found to have been acquired by an intravenous mechanism: blood transfusion or drug use.

Adult

[Chronic eosinophilic pneumonia. An analysis of 4 cases].

Chronic eosinophilic pneumonia (CEP) is characterized by non-specific clinical presentation, interstitial radiological signs, peripheral acini and pulmonary infiltration by eosinophils, accompanied or not by peripheral eosinophilia. Response to treatment with steroids is spectacular. We describe 4 patients with CEP, one diagnosed by response to treatment and the others by bronchoalveolar lavage (BAL). No patient had asthma; 1 also had peripheral eosinophilia. All received long-term treatment with steroids, and there were no relapses. Response to treatment was slow in 2 patients, but obliterans bronchiolitis with or without organizing pneumonia could not be demonstrated. We emphasize the safety and efficiency of BAL for diagnosis of CEP.

Aged

Inversion polymorphism and accumulation of lethals in selected lines of Drosophila melanogaster.

Five long-term selected lines of Drosophila melanogaster were monitored for the presence of lethals and inversions on the third chromosome for a period of nearly 100 generations after the cessation of selection. The results provide an example of the action of inversions as a trap for genes with homozygous detrimental effects in small populations. Lines polymorphic for cosmopolitan inversions In(3R)C and In(3L)P maintain linked lethal and detrimental genes in a near-balanced system. Consideration of the high selection response attained despite inversion polymorphism leads to the conclusion that extreme responses to selection can be obtained without exploiting the potential from large genomic regions.

Animals

Pathophysiology of HIV related thrombocytopenia: an analysis of 41 patients.

AIM: To analyse the pathogenic mechanism of HIV related thrombocytopenia. METHODS: Forty one patients with thrombocytopenia and HIV-1 infection were investigated over two years. Anticardiolipin antibodies were measured using an enzyme linked immunosorbent assay and antiplatelet antibodies were measured using an immunocapture technique. Tests for VDRL, C3 and C4, antinuclear antibodies and rheumatoid factor were also carried out in all patients and 80 control subjects (HIV-1 positive but non-thrombocytopenic). Indiumoxine labelled platelets were transfused in 13 patients. P24 antigen were also measured in 12 bone marrow aspirates. RESULTS: Antiplatelet antibodies and circulating immune complexes were found exclusively in the thrombocytopenic group; values for antiplatelet antibodies and circulating immune complexes were both higher in homosexual and bisexual patients. Three kinds of pattern were observed using 111 In-labelled platelets: splenic (n = 10); hepatic (n = 2); and destruction of bone marrow in just one case. The two most influential factors in the sequestration pattern were antiplatelet antibodies in the splenic uptake and circulating immune complexes in the hepatic and marrow sequestration. All patients, except three, had decreased platelet recovery. In those patients with a CD4 lymphocyte count of less than 200 x 10(6) cells/l the recovery was clearly greater (53%) than in patients who had more than 200 x 10(6) /l (28%). Finally, in seven of the 12 patients who were chosen for immunohistochemical study, p24 antigen was detected in the megakaryocytes, verifying that HIV-1 infects such cells. CONCLUSIONS: The pathogenic mechanism of HIV related thrombocytopenia is probably multifaceted. Antiplatelet antibodies and circulating immune complexes would cause peripheral destruction in the spleen, liver, and bone marrow, in that order; and, on the other hand, there would be an ineffective immune thrombopoiesis and direct infection of the megakaryocytes which could cause a change in the function and maturity of these cells.

Antigen-Antibody Complex

[S. pneumoniae sternoclavicular arthritis in a patient with HIV infection].

HIV infection is a predisposing factor for pneumococcic infection. While pneumonia is the most frequent location, other locations (articular, meningeal, endocardiac, etc) have been less frequently described. Among the articular infections described in patients with HIV infection, the sternoclavicular affection is extremely rare and it usually develops in association with parenterally drug addiction, being Staphylococcus aureus and Pseudomonas aeruginosa the most frequently germs involved. We describe the first case of sternoclavicular arthritis by Streptococcus pneumoniae in a patient with HIV infection. In our case, the chronic hepatopathy associated to alcohol consumption is a predisposing factor related to the pneumococcic infection. Our case suggests the need to formally investigate the HIV infection in young patients with invasive pneumococcic infection.

Adult

Bioequivalence study for diazepam commercial tablets in psychiatric patients.

The bioequivalence of three different commercial diazepam tablets (5 mg) using the innovator product (Valium, Roche) as a reference was evaluated in eight psychiatric patients, following a multiple-dose regimen (5 mg t.i.d.). Each patient received the four treatments sequentially according to a Latin square design, with balance for first residual effect. Blood samples were taken once the steady state of the drug had been reached, and the plasma levels were determined using a HPLC method. No statistical differences were found in diazepam steady-state levels after the administration of the four formulations, indicating that they could be considered equivalent.

Administration, Oral

The distribution of spontaneous mutations on quantitative traits and fitness in Drosophila melanogaster.

Starting from a completely homozygous population of Drosophila melanogaster, two groups of 100 inbred lines each were established and maintained for 46 generations, by a single brother-sister mating and two double first cousin matings, respectively. Sternopleural bristle number, wing length and wing width were simultaneously scored in all lines every 4-5 generations. The means of four lines in each group departed significantly from the overall mean and, in each case, this was attributed to a single mutation of relatively large effect on at least one trait (0.3-1.4 environmental standard deviations in absolute value). Further analyses revealed widespread pleiotropy, similar gene action of a given mutation for all traits affected, and predominant additive action. No apparent association was found between the magnitudes of mutational effects on the traits and fitness. However, all recessive mutations were deleterious. The distribution of mutant effects was asymmetrical (positive for bristles and negative for wing measurements). Moreover, these distributions had a high variance and may be leptokurtic, due to the presence of major genes. Estimates of the ratio of new mutational variance to environmental variance ranged within (0.7-3.4) x 10(-3), those for wing measurements being generally larger. In agreement with theory, the rate of between-line differentiation was independent of population size.

Animals

Ultrastructure and cell wall composition in cell division cycle mutants of Schizosaccharomyces pombe deficient in septum formation.

A number of temperature-sensitive cdc- mutants of Schizosaccharomyces pombe that are affected in septum formation were analyzed with respect to their ultrastructure and the composition of their cell wall polymers. One mutant strain, cdc 16-116, has a cell wall composition similar to the wild type (strain 972 h-). However two other mutants, cdc 4 and cdc 7, show a higher galactomannan content and a lower alpha-glucan content. In all the mutants tested, total glucose incorporation, protein, RNA and DNA synthesis increased similarly to wild type over 3 1/2 h. After 2-3 h of incubation at the non permissive temperature -35 degrees C-, cell numbers remained constant although, increases in optical densities at 600 nm were observed. According to scanning electron microscopy, the mutants had aberrant shapes after 5 h of incubation at 35 degrees C. Transmission electron microscopy showed that cdc 3 is unable to complete septum formation. cdc 4 showed the most varied morphological shapes and aberrant depositions of cell wall material. cdc 8 exhibited a deranged plasma membrane and cell wall regions near of cell poles; an abnormal septum and several nuclei. cdc 7 showed elongated cells with several nuclei and with an apparently normal cell wall completely lacking in septum and septal material. cdc 16 showed more than one septum per cell.

Cell Cycle

Inclusion of laboratory test results in the surveillance of infectious diseases.

We studied certain indicators of the speed with which infectious diseases were notified and epidemiological case records carried out by public health workers for notifications with and without inclusion of laboratory test results. The notification records for brucellosis, dysentery, typhoid fever, viral hepatitis, meningococcal meningitis, and pulmonary tuberculosis in the province of Barcelona between 1982 and 1986 have been reviewed. For each disease notified the time lapse between the onset of symptoms and notification (Delay 1), between notification and implementation of the epidemiological investigation (Delay 2), and the sum of both time lapses (Delay 3) were calculated. In all diseases (with the exception of meningococcal meningitis) when significant differences in delays were noted, the longest were found in those notifications that included laboratory data in the epidemiological investigation. This means that the provision of laboratory data makes the process of notification slower (Delays 1, 2, and 3). Both notification when laboratory results are available and the inclusion of laboratory data in the epidemiological investigation, have a negative influence on the speed of the statutory notification process.

Communicable Disease Control

[AIDS: clinical and necropsy correlation. Analysis of 45 patients].

We have reviewed the autopsies performed on 45 AIDS patients who died in our hospital until June 1989, comparing the post-mortem diagnosis with those made while the patient was alive and in his last hospital admission. Bacterial pneumonia, CMV infection and atypical mycobacteria were the diseases most frequently unnoticed. On the contrary, HIV encephalitis and pulmonary mycosis were the disease with the greatest number of non confirmed clinical diagnosis. The routine performance of necropsy studies to AIDS patients permits to know the most prevalent infections in our environment and should improve the diagnostic precision.

Acquired Immunodeficiency Syndrome